Powertrain Controls - ECM/PCM

DTC 22:

TP Sensor Circuit:

CIRCUIT DESCRIPTION:
The Throttle Position (TP) sensor has a potentiometer whose resistance changes along with the throttle valve position. The ECM provides a 5.0 volt reference to the sensor. The ECM reads the voltage across the sensor and converts it into throttle position. When the sensor resistance decreases, indicating the throttle valve opening is increasing to wide open throttle, the voltage being monitored at the ECM increases. When the sensor resistances increases, indicating the throttle valve opening is decreasing to idle, the voltage being monitored as the ECM decreases. DTC 22 will set if the following condition is met for at least 2 seconds; Low voltage input at the ECM indicated with the engine running off idle.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Measures throttle position sensor signal voltage at sensor. Checks for short to ground in LT GRN/WHT wire.

2. Checks for reference voltage from the ECM.

DIAGNOSTIC AIDS:
DTC 21 and DTC 22 stored at the same time could be the result of an open LT GRN wire.